Network nodes are capable of receiving and forwarding packets being sent through a communications network. A network node may take the form of one or more routers, one or more bridges, one or more switches, one or more servers, or any other suitable communications processing device. A packet, which may also be referred to as a “message” herein, is a formatted unit of data that typically contains control information and payload data. Control information may include, for example: address information, error detection codes like checksums, and sequencing information. Control information is typically found in packet headers and trailers, and payload data is typically found in between the headers and trailers.
Packet forwarding involves decision processes that, while simple in concept, can be complex. Since packet forwarding decisions are handled by nodes, the total time required to perform packet forwarding decision processes can become a major limiting factor in overall network performance.
Another factor that can affect network performance is, of course, the integrity of the network itself. For example, a non-functioning link between a pair of network nodes can result in lost packets or in network delays caused by re-routing of packets. Operations, Administration and Maintenance (OAM) activities include operations designed to monitor or measure network path variables such as packet loss or transmission delay.